A:6ab
B:12ab
C:0
D:24ab
下列各句中,加横线的成语使用恰当的一句是( )
— Mum, I've got a chance to be an exchange student to the UK next year!
— Really? That's just ________ to be true. Anyway, congratulations, baby!
如图是部分食肉目动物分类等级示意图,据图回答问题